(1) Field of the Invention
The invention relates in general to the technical field for binding loose-leaf papers, and more particularly to a loose-leaf binder, which can be operated in a light, handy and low-effort manner and has the enhanced beauty and standing stability.
(2) Description of the Prior Art
Typically, the methods of binding books may be classified into a fixed binding method and a loose-leaf binding method, wherein the fixed book has inner stacked pages with lateral side edges being adhered, and has the advantage that the inner pages cannot be easily peeled and lost, but has the drawbacks that the book cannot be effectively leveled, that the use of the inner edge is affected, that the user has to use his/her hand to smoothen the book so that the writing can be easily performed, that the inner pages cannot be updated, added or removed, and that other inner pages are often successively detached once one of the inner pages is detached so that the notebook is damaged. In the loose-leaf book, the lateral side edge of the inner stacked page is formed with one row of binding holes, and a helical binder coil disposed on a board sequentially passes through the binding holes, so that the inner pages are selectively mounted to the helical binder coil, and then the helical binder coil is closed. The advantage thereof is that the inner pages can be deployed by 360 degrees. However, the drawback thereof is that the outer diameter of the helical binder coil has to be greater than a double of the thickness of the book for the purpose of easy use. However, such configuration causes the pages to become loose to cause the indecent phenomenon and affect the beauty thereof. In addition, the helical binder coil needs to be rotated upon loading or unloading of the inner pages, so that the helical binder coil sequentially goes into or out of each binding hole in a helical manner. In addition, the helical binder coil needs to be completely detached from the loose-leaf book, so that the inner pages of the loose-leaf book can be replaced. However, such the loading and unloading method is extremely time-consuming, and cannot be easily operated so that a lot of inconvenience in use may be caused.
In view of the above-mentioned problems of the conventional loose-leaf book, the present inventor has developed a loose-leaf binder with the easy loading and unloading in U.S. Pat. No. 7,341,390 B2, wherein the loose-leaf binder is composed of an open coil formed on one side, a back engaging with an opening of the coil in a sliding manner, and two end plugs inserted into two ends of the back. After the inner loose-leaf pages are loaded from the opening of the coil, the back may directly slide to close the opening of the coil. Then, the end plugs on the two ends prevent the coil from coming off to achieve the object of forming the loose-leaf book. On the contrary, when the inner pages need to be replaced, added or removed, the end plugs are reversely removed and the back can be moved out, so that the attachment and detachment become easy.
However, when the inner pages of the loose-leaf binder are to be replaced, added or removed, the end plugs are inserted into the two ends of the back by the large frictional force between the inner surface of the back and the end plug. When the gap therebetween is too large and causes the too-loose condition, the end plug tends to slip out. If the gap therebetween is too small and causes the too-tight condition, the end plug cannot be easily inserted, and a larger force is needed to remove the end plug so that the end plug is frequently damaged. Furthermore, the end plug tends to be combined with the coil and the end portion of the coil tends to be pulled out when the end plug is pulled out, thereby affecting the overall operation smoothness. In addition, one hand needs to press the latch of the end plug passing through the back, and the other hand's thumb and index fingers need to nip the end plug cover and pull it out, so that the end plug can be separated from the back. Thus, two hands have to be used to complete the overall attachment and detachment operations of the end plug. In addition, when the fingers nip the end plug cover, the area thereof is smaller, and the fingers often nip the two sides of the end portion of the back, so that the friction force for pulling out the end plug is increased to cause the trouble in operation. In addition, when the coil passes through the back, the coil is somewhat compressed longitudinally. Because the coil is not effectively positioned, rubbing and twitching of the coil often occur after the end plug is pulled out, and the coil tend to come off or fail due to the deformation. Thus, the loose-leaf binder still has some drawbacks to be improved.
In view of this, the prevent inventor has paid attention to the research and development to overcome the problems of the existing loose-leaf binder according to the experience and the technology in researching and developing the associated products for many years, and thus developed this loose-leaf binder to overcome the troubles that the existing positioning effect is poor, that the deformation is caused due to the frictional force for pulling the end plug, that the operation is laborious and that both hands are needed to complete the operation.